DataDesc is used to store name, shape, type and layout
information of the data or the label.

The layout describes how the axes in shape should be interpreted,
for example for image data setting layout=NCHW indicates
that the first axis is number of examples in the batch(N),
C is number of channels, H is the height and W is the width of the image.

For sequential data, by default layout is set to NTC, where
N is number of examples in the batch, T the temporal axis representing time
and C is the number of channels.